The teachings presented herein relate generally to stereoscopic images. More specifically, the teachings presented herein relate to the creation of stereoscopic images by printing on transparencies.
The principle of stereoscopic vision is well understood. At the most basic level, each of the viewer's two eyes must perceive the subject matter to be viewed from a slightly different perspective. That is to say that, although the differences are generally quite subtle, each eye receives a different image.
Several methods are commonly used to produce stereoscopic images. On the one hand, these include the use of direction selective screens onto which two or more images may be projected simultaneously. Depending on the viewer's position, a different image may be observed by each eye. Where only two images are required, it is common practice to use polarizing techniques. Each image is projected with a characteristic polarization and when viewing through complementary polarizing viewing spectacles, each eye only sees the picture intended for its reception.
Most existing methods to view printed stereoscopic images require either special glasses (colored or polarized) or lenticular lenses. The stereogram may be the one exception which does not need any special viewing aid; however, many people find that it is very difficult and uncomfortable to see the hidden stereo image. Lenticular lenses are common but incur some additional expense and complexity as they require an embossed transparent material for operation.
What is needed is a method and apparatus for providing stereoscopic images that are viewable without the need for lenticular or other special lenses which may be readily and inexpensively provided with common materials using conventional printing apparatus.
Disclosed in embodiments herein is a moiré-based auto-stereoscopic rendered image. The rendered image comprises a transparent substrate having a front side and a back side. As applied to and placed on the front side of the transparent substrate is a front-side applied marking material of periodic structure having a first frequency. As applied to back side of the transparent substrate is a back-side applied marking material of periodic structure having a second frequency, that second frequency being some delta away from the first frequency such that when the transparent substrate is viewed from either side a moiré-based auto-stereoscopic rendered image is evident.
Further disclosed in embodiments herein is an alternate moiré-based auto-stereoscopic rendered image. The rendered image includes a transparent substrate having a first side and a second side, with a first side applied marking material having a periodic structure at a first frequency, as applied to and placed on the first side of the transparent substrate. The rendered image also includes a second side applied marking material as applied to the second side of the transparent substrate, that second side applied marking material further comprising a first partition and a second partition, the first partition having a periodic structure at a second frequency, that second frequency being related to but some delta away from the first frequency, and the second partition having a periodic structure at a third frequency, that third frequency being related to but some delta away from the first frequency, such that when the transparent substrate is viewed from either side a moiré-based auto-stereoscopic rendered image is evident.
Further disclosed in embodiments herein is an alternate moiré-based auto-stereoscopic rendered image, comprising: a transparent substrate; a first side applied marking material having a periodic structure at a first frequency, as applied to and placed on at least one side of the transparent substrate; an additional substrate having a selected side and, a second side applied marking material as applied to the selected side of the additional substrate which further comprises a first partition and a second partition, the first partition having a periodic structure at a second frequency, that second frequency being related to but some delta away from the first frequency, and the second partition having a periodic structure at a third frequency, that third frequency being related to but some delta away from the first frequency such that a moiré image is rendered.
Further disclosed in embodiments herein is a method for providing a moiré-based auto-stereoscopic rendered image, by applying marking material with a halftone periodic structure at a first frequency to the first side of a transparent substrate. The method further comprises applying marking material within a first partition on the second side of the transparent substrate with a halftone periodic structure at a second frequency, that second frequency being related to but some delta away from the first frequency. The method also comprises applying marking material within a second partition on the second side of the transparent substrate with a halftone periodic structure at a third frequency, that third frequency being related to but some delta away from the first frequency such that a auto-stereoscopic moiré image is rendered.